Railway traffic controlling apparatus



July 23, 1940. R, PFLASTERER 2,208,685

RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 15, 1937 5 Sheets-Sheet 1 5T 11* my. 1A. BM 65 INVENTOR George 13. aszeren HA5 ATTORNEY 6 P 8 1 W m C m L T 0% C m 9. Q T 1 6 v 5 illillw. 1 1| v v k B W 4 m B Y B 6 B0 3 II WV 9\ A4 A B B 5 h ,5 HM i i i H m B R C July 23, 1940 G. R. PFLASTERER RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 15, 1937 5 Sheets-Sheet 5 INVENTOR George 13.

H13 ATTORNEY y 1940. ca. R. PFLASTERER 2,208,685 I RAILWAY TRAFFIC CONTROLLING APPARATUS Filed May 15, 1937 5 Sheets-Sheet 5 p e Q p E MNQQN M LN m N m m m Q v T w P M wmmwj MR NE t 3 Q 51 Y 1 e H 8 mm. wxm EN 2% 3% $5 m m E fiflfi. Q w m En I MSQ 8E gw fil hi w ma? 5% msv 3 QSQ MEN AWE Q WE D N N MNM B 2% 3% aw NB. mw WEN R3 QNN Y MNBN r 5w @TU ufi QE mi o Ev MR 2% EN @Q wsw Patented July 23, 1940 TRAFFIC CONTROLLING APPARATUS RAILWAY George It. Pilaster'er, Swissvale, Pa., assignor to The Union Switch -& Signal Company, Swiss vale, Pa., a corporation of Pennsylvania Application May 15, 1937, Serial No. 142,847

31 Claims.

My invention relates to railway traffic controlling apparatus of the type involving switches and signals, and more particularly to apparatus for automatically positioning the switches and signals upon the approach of a train.

I shall describe two forms of apparatus emas the reference character of the actuating relay.

Referring first to Figs. 1A and 1B, thereferencecharacter X designates a stretchof railway track which is divided by insulated joints into a detector'section 5'1 and two approach sections IT and 2T, respectively. The detector section -Tincludes an intersection with another .stretch of railway track which is designated by the reference character Y and which includes two approach sections 3T and AT. As here shown, the intersection between stretch X and stretch Y includes two switches designated by the reference characters A and F, respectively. For governing the movement of trafiic over the intersection; ,tracl: X is provided with signals l and-2, and

.track Y is provided with signals 3 and 4. Each track section is provided with a track circuit including the usual track battery I and a track relay designated by the reference character R. witha prefix the same as the'reference character of the associated track section.

The switches A and F are of the well-known dual control type. For example, switch A is pro vided with a selector lever SA which operates a link 8A. When lever SA is in its normal position,

as shown in the drawings, link 8A connects switch .A with motor MA, and when lever S is inits .lreve-rse position, link 8A disconnects switch A @from motor MA and connectsfthe switch with hand throw lever HA. Selector lever I-IA also controls a contact 9 which is closed only when .the selector lever SA is in its normal position as shown in the drawings. Switch F is provided with similar control apparatus including a selector zbodying my invention, andshall then point out.

.a reference character having a prefix the same (01. 246-134) I lever SF, link BF, hand, throw, lever HF and a contact Iii which is closed only when the selector lever SF is occupying its normal position. Switch A controlsa pair-of pole changing contacts I I and I2 as well ascontacts l3 and M, the. con- 5;

tacts l3 and I4 being closed only when switch .A is in itsnormal and reverse positions, respectively. Switch'li' controls a pair of pole changing contacts 15 and It as well as contacts, l1

and IS, the contacts I! and l8 being closedonly .lO

when switch F is in itsnormal and reversepositions, respectively. I- 3 Each switch is provided with a polarized control relay designated by.v thereference character Wl-twith.v a prefix, the same as the reference .1 character, of. the associated switch When-the switch control relays AWR. and FWR are energized in one directiomthe switch-motors MAv and are caused to drive the-associated.switchtq a corresponding positionwhereas, when the relays AWR and FWRare .-energized in the otherdirection, the associated switchis caused to assun e the opposite position. .In order to simplify the drawings, the, detailed circuits for the control of motors MA and MF- by relays AWR and FW-R. .25

respectively, have been omitted. r

For indicating the position of switches A and F, each switch is provided with a polarized indication relay designated by the reference char- ;acterKR with a prefix the same "as the reference .30 character of theassociated switch.

I For, preventing .theoperation of motors andMF :whenv either switch A or switch F,is conditioned for rnanual operation, I- provide a :lock,relaygdesignated by the reference charaoter LS. g I I I I For preventingtheclearing of the signals by a receding' train, ,each approach section is pro- -vided with a directional stick relay designated .bythe referencecharacter SR with a preiixthe 40 .sameas the prefixwin the reference characterfor the associated approach section. I

For controlling the switches and signals upon the approachof a train, I provide the track X with-a neutral relay'used as an approach relay designated by the reference character XAR and thetrack Y with'an' approach relay designate by the reference character YAR.

For controlling the signals, I'pr'ovide for each 1 a. signal a signal controlrelay or route relay des- "ignated by the' reference character HR with [a prefix thesarne the reference character of the associated signah .In order to simplify the drawings, Il ave omitted the usual circuits for controlling the signals by the associated signal control relay HR.

Each approach section is provided with an paproach locking relay designated by the reference character MR with a prefix the same as the reference character of the associated approach section.

I provide the tracks X and Y with timing devices or time contactors XTE and YTE, respectively, in the event that it is desired to change the route for a train on one track after the route has already been set up for a preceding train on the other track.

Having thus described in general the apparatus shown in Figs. 1A and IE, I shall now describe the operation of the apparatus.

With switches A and F in their normal position and with all signals at stop, as shown in the drawings, I shall first assume that a train on track Y desiring to proceed from section 4T to section 3T enters section 4T to release track relay 4TR. The opening of front contact 01 relay 4TB. will release approach relay YAR (see Fig. 1B). The closing of back contact 2| of re lay YAR will establish a stick circuit over front contact 22 of relay XAR for the latter relay so that relay XAR cannot become released in the event that approach sections IT or 2T become occupied by another train while section AT is occupied.

The releasing of relay YAR establishes a circuit for energizing switch control relays AWR and FWR in the reverse direction to cause switches A and F to move to their reverse positions. The circuit for relays AWR'and FWR may be traced over a path from terminal B of a suitable source of energy through back point of contact 23 of relay YAR, front point of contact 24 of relay "XARfirelays AWR and FWR in multiple, front contact 25 of lock relay LS, front contacts 26, 21, 28, 29 of approach locking relays 4MB, 3MB, 2MB, and MR, respectively, front contact of track relay 5TR, front point of contact 3| of approach relay XAR, and back point of contact 32 of relay YAR to terminal C of the same source of energy. When the switches A and F are in their reverse positions, circuits will be established for energizing the indication relays AKR and FKR in the reverse direction. The circuit for indication relay AKR may be traced from terminal B (see Fig. 1A) through contact In of selector lever SF, contact 9 of selector lever SA, contact ll of switch A, reverse polar contact 34-35 of switch control relay AWR, relay AKR, and contact |2 of switch A to terminal C. The circuit for indication relay FKR may be traced from terminal B through contact ll] of selector lever SF, contact 9 of selector lever SA, contact l5 of switch F, relay FKR, reverse polar contact 363'| of relay FWR, and contact l6 of switch F to terminal C.

Since relays AWR and FWR are energized in the reverse direction and relays YAR and 4TR are released, the reversal in the direction of energization of relays AKR and FKR establishes a circuit for signal control relay 4HR. so that signal 4 will be caused to assume its proceed condition. The circuit for signal control relay 4HR may be traced from terminal B (see Fig. 13) over a path through front contact 39 of approach relay XAR, back contact 40 of approach ,relay YAR, front contact 4| of track relay 5TH, front contact42 of approach locking relay 2MR, front contact 43 of approach locking relay IMR, front neutral contact 44 and reverse polar contact 45-46 of switch indication relay FKR, front neutral contact 41 and reverse polar contact 48-49 of switch indication relay AKR, reverse polar contact 5|l5| of switch control relay FWR, reverse polar contact 52-53 of switch control relay AWR, normal contact 54 of timing device XTE, front point of contact 55 of relay 3TR, back point of contact 56 of relay 4TB, front contact 51 of approach locking relay 3MR, back contact 58 of directional stick relay 48R, and relay 4H8 to terminal C. The closing of front point of contact 60 of relay 4HR will supply energy to signal 4 over the usual signal operating circuit (not shown) and the opening of back point of contact 60 of relay 4I-IR will release approach locking relay 4MR. The releasing of approach locking relay 4MR insures that no other signal control relay can be energized and that the direction of energization of relays AWR and FWR cannot be changed in the event that one of the approach sections for track X becomes occupied by another train.

When the train enters section 5T, directional stick relay 33R will become picked up over a circuit which passes from terminal B (see Fig. 1A) through reverse contact N3 of switch F, back contact 6| of track relay 5TB, front contact 62 of approach locking relay 3MB, and relay 38R to terminal C. When relay 38B is picked up, it will be maintained in that condition when the train enters section 3T by a stick circuit which passes from terminal B through back contact 63 of track relay 3TR, front contact 64 of relay 38R, and relay 3SR to terminal C. The picking up of directional stick relay 38R opens its back contact 69 in the control circuit for signal control relay 3HR so that the latter relay cannot become energized to clear signal 3 while the train occupies section 3T.

The opening of front contact 4| of track relay 5TR when the train enters section 5T will, of 5 course, deenergize signal control relay 4HR so that signal 4 will be caused to assume its stop condition.

When the train vacates section 5T, approach locking relay 4MB. will become energized over a pick-up circuit which passes from terminal B through back point of contact 60 of relay 4HR, front contact 65 of relay 5TB, front contact 66 of relay 4TB, and relay 4MB. to terminal C. The picking up of directional stick relay 3SR will provide a stick circuit for approach relay YAR over a path which passes from terminal B through front contact 68 of relay 33R, front contact 20 of relay 4TR, and relay YAR. to terminal C. The

opening of back contact 2| of relay YAR will disconnect energy from the previously traced stick circuit for approach relay XAR so that the latter relay willbecome released in the event that a train enters either section IT or 2T on track X. The switches A and F, therefore, and signals and 2 maybe properly positioned for a movement on track X even though the receding train still occupies approach section 3T of track Y. When the train vacates section 3T, the opening of back contact 63 of relay 3TB will release directional stick relay 38R and the opening of front contact 68 of relay 38R will again place approach relay YAR under the control of front contact .10 of relay 3TR and front contact 2|] of relay 4TB. The closing of back contact 69 of relay 38R will place signal control relay 3HR condition.

A train occupying section IT or 2T of track x and moving toward the intersection will position the switches A and F and clear eithersignal I or signal 2 in a manner similar to that just described for the train movement from section 4T to section 3T of track Y. Likewise,- a movement in the opposite direction} on track Y will position the switches A and F and clear signal 3 in a similar manner.

I shall now assume that,with all apparatus-in its normal condition as shown in the drawings, a train occupying section lTof track X desires to move to section 31' of track Y; Switch Abeing in the normal position, the train may, of course, proceed to switch F; Upon reaching switch F, the tr-ainman will reverse selector lever SF to connect switch F to hand throw lever I-IF so that switch F can be manually moved to its reverse position. The reversal of selector lever SF will open contact It! so that look relay LS will'become released to prevent energization of switch control relays AWR or FWR. After theswitch F is placed in its reverse position, the selector lever SF will again be restored to its normal position. If the train enters section 5T, the release of track relay 5TB. will establish'a pick-up circuit for relay LS. This circuit may be traced from terminal B through contact I!) of selector lever SF, contact 9 of selector lever SA, back contact H of relay 5TB, and relay LS to terminal C. If the train for any reason fails to enter section 5T, another pick-up circuit for lock relay LS is provided which circuit will become closed only in the event that all approach sections are unoccupied. This' circuit may be traced from terminal B through contact In of selector lever SF, contact 9 of selector lever SA, front contact 12 of track relay 4TB, front contact 13 of track relay ITR, front contact M of'track relay ZTR, front contact 15 of track relay 3TB, and relay LS to terminal C. When relay LS is in its picked up condition and selector lever SA and SF are both in their normal condition, a stick circuit is established for lock relay LSto maintain relay LS in its normal energized condition even though'the approach sections are occupied. This stick circuit may be traced from terminal 3' through contact I0 of selector lever SF, contact 9 of selector lever SA, front contact 16 of relay LS, and.

relay LS to terminal C, It will be seen, there-. fore, that when relay LS is released, this relay may again be energized only if the detector section becomes occupied or if all approach sections become unoccupied. 'Thisfeature insures that when the selector levers SA and SF are returned to their normal positions 'to connect switches A and F to motors MA and MF, respectively, energy cannot be supplied to the switch motors unless trafiic conditions are such that it is safe to do so. i

As hereinbefore pointed out, the timingdevices YTE and XTE are provided to effect a change in the route. In order to explain the operation of the timing devices YTE and XTE, I s-hall assume that the switches A and F are in their normal position and that signal control relay II-IR. is energized in response to' a train occupying approach section IT and that another train occupying section 4T desires to proceed over the intersection ahead of the first'train. The opening of front contact Bil of track relay ITR will, of course, release approach relay XAR to'establish a stick circuit for approach relay YAR over back contact 8| of relay XAR and front contact ll of relay 'YAR. The energizing of signal control relay II-lR will release'approach locking relay IMR because back contact 82of relay [HR is open. In order to change the route, it will, of course, be necessary to pick up approach relay XAR and locking relay IMR and to release ap proach relay YAR. The trainmanon the train occupying section 4T may do this by reversing timing device YTE and then permitting device YTE to return to its normal position. When device YTE is reversed, normal contact 83 in the control circuit for signal control relay 1BR will become opened and reverse contact 84 in a pickup circuit for approach relay XAR will become closed. Signal control relay II-IR, therefore, will become released to cause signal I to indicate stop and approach relay XAR will become picked up so that the opening of its back contact 8| will release approach relay YAR. At the expiration of a given time interval (approximately ten seconds before device TE" completes its operation), contact 85 of device YTE will become. closed to establish a pick-up circuit for approach locking relay IMR. When relay IMR is picked up, it will be maintained in that condition by a stick cir cuit which passes from terminal B through back point of contact 82 of relay lI-IR, front contact 36 of relay IMR, and relay IMR to terminal C. When the device YTE completes its operation, normal contact 83 of device YTE will, of course, become closed but relay IHR will not become energized because front contact 18 of relay YAR and back contact 19 of relay XAR are both now opened. Since approach relay YAR. is'now released and approach relay XAR is now picked up, the switches A and F will. assume their reverse positions in a manner similar to that previously described for a movement from section 4T to section 3T. As soon as app-roach locking relay IMR becomes picked up, therefore, to close its front contact 43, the previously traced control circuit for-signal control relay tl-IR will become energized to cause signal 4 to display the'proceed indicationfo-r the train occupying section 4T. When that train has entered detector section 5T to pick up relay 3SR, relay YAR will'become picked up so that approach relay XAR will become released. The releasing of relay XAR and picking up of relay YAR will supply energy in the normal direction to relays AWR and FWR as soon as the first train vacates section 5TB. An energizing circuit, therefore, will be closed for signal control relay IHR, to cause signal I to display the proceed indication for the train occupying IT as soon as the other train has cleared section 5T.

Referring now to Figs. 2A, 2B, 2C, and 2D, 'the reference character W designates a stretch of single track which includes the detector section ET and which is connected at one end by the switch F to tracks V and Vi of a stretch of double track and at the other end by the switch A to tracks Z and Zi of another stretch of double track. The tracks Z, ZI, V, and V! are provided with the usual approach sections including track relays 4TB, ITR, 2TB, and 3TH, respectively, and the section ST is provided with the usua track relay 5TB. The normal direction for eastbound trafli that is, traffi'c moving from left to right, is, as indicated by the arrows, from track Z! to track V! and the normal direction for westbound traffic is, as indicated by thearrows, from track V to track Z. However, as will be explained more in detailhereinafter, the switches A and F and associated signals I, 2, 3. and A are automatically 'positioned'to route eastbound trains in sections IT and 4T to section 3T, and to route westbound trains in sections 2T and 3T to section 4T.

Each switch is provided with a lock relay designated by the reference character LS with a prefix the same as the reference character of the associated switch. The relays ALS and FLS are controlled in a manner similar to that described for relay LS shown in Fig. 1A. For example, relay ALS is provided with a stick circuit which includes contact 9 of selector lever SA and front contact 90 of relay ALS and is also provided with two pick-up circuits. The first pick-up circuit includes,- contact 9 of selector lever SA and back contact 9! of track relay 5TB, and the second pick-up circuit includes contact 9 of selector lever SA, front contact 92 of relay ITR, and front contact 93 of track relay 4TR.

Each switch is provided with the usual switch control relays AWR and FWR, respectively, and

20 with the usual switch indication relays AKR and FKR, respectively. Each signal is provided with the usual signal control relay HR and each signal control relay HR controls the usual approach locking relay MR. Each approach section is also provided with the usual directional stick relay SR.

Eachapproach section is provided with a primary and a secondary approach relay designated by the reference characters AR and AS, respectively, each with a prefix the same as the prefix in the reference character of the associated approach section.

Each approach section is provided with a timing device designated by the reference character TE with a prefix the same as the prefix in the reference character of the associated approach section.

Each primary approach relay AR is controlled in the usual manner by the associated track relay TR and by the associated directional stick relay SR so that the approach relays will become released when the associated approach section becomes occupied by a train approaching the stretch W but not when such approach section becomes occupied by a train receding from stretch W. Each primary approach relay AR is also controlled in the usual manner by the approach relays AR and by the timing devices TE associated with certain of the other approach sections so that after a route has been established by the occupancy of one approach section by a train such route cannot be changed by the entrance of another train into one of the other approach sections but can only be changed by an operation of the proper timing device TE.

Each secondary approach relay AS is provided with a slow release characteristic and is controlled by the associated primary approach relay AR and certain of the other primary approach relays AR in such a manner that, as will be explained more in detail hereinafter, precedence is conferred on trains occupying certain of the approach sections in the event that two or more approach sections become occupied simultaneously by trains approaching stretch W.

Having thus described in general the apparatus shown in Figs. 2A, 2B, 2C, and 2D, I shall now describe its operation.

I shall first assume that an eastbound train on track ZI enters section IT so that track relay ITR becomes released. The opening of front contact I of track relay ITR (see Fig. 23) deenergizes primary approach relay IAR so that the latter relay'becomes released. The releasing of relay IAR causes its front contact IIlI to become opened to deenergize secondary approach relay .IAS-andthe closing of back contactsIIlZ and H13 of relay IAR establishes stick circuits for approach relays4AR and ZAR, respectively so that these relays cannot become releasedif the associatedapproach section becomes occupied by another :train. The stick circuit for primary approach relay. 4AR includes back contact I02 of relay IAR and front contact I04 of relay 4AR. The stick circuit for primary approach relay ZAR includes back contact I03 of relay IAR and front contact I95 of relay ZAR.

When relay I AS becomes released, a circuit will be established for energizing switch control relay AWR in the reverse direction and a circuit will be established for energizing switch control relay FWR in the normal direction. The circuit for relay AWR may be traced over a path from tere minal B through back point of contact I06 of approach relay IAS, front points of contacts I01, I98, andI09 of approach relays 4AS, 3A8, and 2A8, respectively, relay AWR, front contact I III of locking relay. ALS, front points of contacts III, H2, and H3 of approach relays ZAS, 3A8, and 4A5; respectively, back point of contact II4 of a proach relay IAS, front contact II of track relay 5TB, and front contacts H6, H1, H8, and H9 of approach locking relays 4MB, 3MB, ZMR, and IMR, respectively, to terminal C. The circuit for switch control relay FWR may be traced over a path from terminal B through front point of contact I29 of relay 2AS, back point of contact I2I of relay IAS, front contact I22 of lockf ing-relay FLS, relay FWR, back point of contact I23of approach relay IAS, front point of contact I24 of approach relay ZAS, front contact H5 of track relay 5TR, and thence over the same path as tracedfor relay AWR to terminal C.

When switch A attains its reverse position, polarized switch indication relay AKR will be energized in the reverse direction by a circuit which may be traced over a path from terminal B (seeFig. 2A) through contact 9 of selector lever SA, reverse contact II of switch A, reverse polar contact I25-I26 of relay AWR, relay AKR, and reverse contact I2 of switch A to terminal G. Since switch F is already in its normal position, polarized switch indication relay FKR will remain energized in'the. normal direction by a circuit which may be'traced over a path from terminal B through contact I ll of selector lever SF, normal contact I5 of switch F, normal polar contact I'Z'I-IZB of relay FWR, relay FKR, and normal switch contact'IIi of switch F to terminal C. Relays IAS and ITR both being released and switch control relay AWR being energized in the reverse direction, a circuit for signal control relay IHR will be established as soon as switch indica tion relay AKRbecomes energized in the reverse direction. This circuit may be traced over a path from terminal B (see Fig. 20) through front contact I30 of relay 5TB, front contact I 3| of relay 2MR, front contact I32 of relay 3lVH't, front contact I33 of relay 2AS, front contact I34 of relay 3AS, front contact I35 of relay 3TR, normal polar contact I36-I31 of relay FWR, front neutral contact I38 and normal polar contact I39-I4Il of relay FKR, front neutral contact MI and reverse polar contact I42-I43 of relay AKR, reverse polar contact I44I45 of relay AWR, front contact I4B-of relay 4AS, back contact I41 of relay IAS, normal contacts I48, I49, and I50 of timing devices ZTE, 3TE, and 4TE, respectively, front contact |5I of relay 4MR, back contact I52 of relay ISR, back contact I53 of relay ITR, and relay IHR to terminal 0.

The resulting energization of signal. control relay II-IR, will cause the front point of its contact I54 to become closed and the back point of its contact I54 to become opened. The closing of front point of contact I54 will establish a signal operating circuit .(not shown) to cause signal I to indicate proceed and the opening of the back point of contact [54 will cause approach locking relay IMR to become released. The releasing of approach locking relay IMR will, of course, prevent energization of either switch control relay FWR or AWR and will also prevent the clearing of any of the other signals in the event that another approach section should become occupied.

' When the train enters section 5T so that relay 5TB, becomes released, directional stick relay 35R will become picked up by a circuit which passes over a path from terminal B (see Fig. 2A) through normal contact I8 of switch F, back contact I55 of relay 5TB, front contact I56 of relay 3MB, and relay 35R to terminal C. Relay 38R, when picked up, will be maintained in that condition while the train occupies section 3T by a stick circuit which includes back contact I51 of relay 3TR and front contact I58 of relay 35R.

The releasing of relay 5TB, will, of course, cause signal control relay IHR to become deenergized so that signal I will be caused to indicate stop and so that approach locking relay IMR can be energized again when the train vacates section ST. The circuit for energizing relay IMR may be traced over a path from terminal B (see Fig.

20) through back point of contact I54 of relay IHR, front contact I59 of relay 5TB, front contact I66 of relay ITR, and relay IMR. to terminal C. Relay IMR is also provided with the usual stick circuit including its own front contact I6I to maintain relay IMR in its energized condition, I

at times when sections IT and ET are occupied by a train moving in a direction opposite to that governed by signal I.

When the train vacates section 3T, track relay 3TB. will, of course, become picked up again to release directional stick relay 38R and thus restore all apparatus to its initial condition.

I shall next assume that sections IT and AT each become occupied simultaneously by eastbound trains so that both track relays ITR and "IITR become released. The opening of front contact I00 of relay ITR (see Fig. 2B) and the opening of front contact I63 of relay 4TB, will simul-,- taneously release primary approach relays IAR and 4AR, respectively. The opening of front contact IIlI of primary approach relay IAR and the opening of front contact I64 of primary approach relay AAR will simultaneously deenergize secondary approach relays IAS and 4A8, respectively. Only secondary approach relay IAS will, however, become released because the closing of back contact I65 of primary approach relay IAR will establish a stick circuit over the front contact I66 of secondary approach relay 4A8 so that approach relay 4AS is prevented from releasing. As a result, the switches A and F and signal I will be properly positioned, as previously described, to permit the train occupying section IT to move over stretch W into section 3T ahead of the train occupying section 4T. In other words, the route from section IT to section 3T is superior to the route frm section 4T to section 3T. When the first train has vacated section 5T, then the switches A and Fand signal. 4 will be properly positioned for the movement of the following train from section 4T through stretch W intosection 3T.

In a similar manner, section 3T issuperior to section IT because secondary approach relay a stick circuit which includes its own front con- I tact I10 and back contact III of primary approach relay ZAR, and sections IT and 4T are superior to section 2T because secondary approach relay ZAS is provided with two stick circuits, one including back contact I12 of primary approach relay IAR, and the other including back contact I13 of primary approach relay IAR, and both circuits including front contact I'M of relay 2A8.

In the event that it is desired to change the route for a train occupying one approach section after the switches and signals have already been positioned by another train occupying another approach section, this may be done by manipulating the proper timing device ITE, ETE, or ITE in a manner similar to that described for themanipulation of timing devices XTE and YTE shown in Figs. 1A and 1B. v

Having thus described the operation of the apparatus embodying my invention for a few train movements, it is believed that the operaing from the spirit and scope of my invention.

Having thus described my invention, what I claim is: v I

s 1. In combination, astretch of railway track including a track switch operable between a normal position and a reverse position, a, first approach section connected with said stretch when said switch is occupying its normal position, a second approach section connected with said stretch when said switch is occupying its reverse position, a mechanism for operating said switch between its two positions, a first relay which becomes released when a train is approaching said switch in said first section, a second relay which becomes released when a train is approaching said switch in said second section, means effective when either relay is re.- leased to maintain the other relayin its picked up condition, and means for causing said mechtil.

anism to operate said switch in its normal position or to'its reverse position according said first or said second relay is released provided the other relay remains picked up.

2. In combination, a stretch of railway track including a track switch operable to a normal position and a reverse position, a first approach section connected to said stretch when said switch is occupying its normal position, a second approach section connected to said stretch when said switch is occupying its reverse position, a mechanism for operating said switch between its two positions, a first approach relay and a second approach relay associated with said first and second approach sections respectively, means for causing said mechanism to operate said switch to its normal position or to its reverse position according as said first or second approach relay respectively becomes released provided the other relay remains picked up, means for releasing each approach relaywhen the associated approach section becomes occupied by a train approaching said switch, means for maintaining each ap-. proach relay picked up when the associated approach section becomes occupied by a train receding from the intersection, and means efifec tive when one approach relay is released to maintain the other approach relay in its picked up condition. s

3. In combination, a stretch of railway track including a track switch operable to a normal position and a reverse position, a first approach section connected to said stretch when said switch is occupying its normal position, a second approach section connected to said stretch when said switch is occupying its reverse position, a mechanism for operating said switch between its two positions, a first approach relay and a second approach relay associated with said first and second approach sections respectively, means for causing said mechanism to operate said switch to its normal position or to its reverse position according as said first or second approach relay respectively becomes released provided the other relay remains picked up, means for releasing each approach relay when the associated approach section becomes occupied by a train approaching said switch, means including directional stick relays for maintaining each approach relay picked up when the associated section becomes occupied by a train receding from the intersection, and means effective when one approach relay is released to maintain the other approach relay in its picked up condition.

4. In combination, a stretch of railway track including a track switch operable to a normal position and a reverse position, a first approach section connected to said stretch when said switch is occupying its normal position, a second approach section connected to said stretch when said switch is occupying its reverse position, a mechanism for operating said switch between its two positions, a first approach relay and a second approach relay associated with said first and second approach sections respectively, means for causing said mechanism to operate said switch to its normal position or to its reverse position according as said first or second approach relay respectively becomes released provided the other relay remains picked up, means for releasing each approach relay when the associated approach section becomes occupiedby a train approaching said switch, means eifective when one approach relay is released to maintain the other approach relay in its picked up condition, and manually operable means for picking up each approach relay to permit the release of the other approach relay.

5. In combination, a stretch of railway track including a track switch operable to a normal position and a reverse position, a first approach section connected to said stretch when said switch is occupying its normal position, a second approach section connected to said stretch when said switch is occupying its reverse position, a mechanism for operating said switch between its two positions, a first approach relay and a second approach relay associated with said first and second approach sections respectively, means for causing said mechanism to operate said switch to its normal position or to its reverse position according to said first or second approach relay respectively becomes released provided the other relay remains picked up, means for'releasing each approach relay when the associated approach section becomes occupied by a train approaching said switch, and means including a timing devicefor each approach relay for picking up such relay to permit the other relay to become released.

6. In combination, a first stretch of railway track including an intersection with a second stretch of railway track, said intersection includ ing a pair of track switches each operable to a normal position to condition said intersection for the passage of traffic in said first stretch and to a reverse position to condition said intersection for the passage of trafiic in said second stretch, a pair of mechanisms for operating said switches between their two positions, a first and a second. approach section in said first stretch, a third and a fourth approach section in said second stretch, and means for causing said mechanisms to operate said switches to their normal positions or to their reverse positions according as a train approaching said intersection is occupying said first or second approach sections or saidthird or fourth approach sections.

'7. In combination, 'a first stretch of railway track including an intersection with a second stretch of railway track, said intersection including a pair of track switches each operable to a normal position to condition said intersection for the passage of traffic in said first stretch and to a reverse position to condition said intersection for the passage of traffic in said second stretch, a pair of mechanisms for operating said switches between their two positions, a first and a second approach section in said first stretch, a third and a fourth approach section in said secondstretch, a first approach relay'which becomes released when a train is approaching said intersection in either said first or said second approach sections, a second approach relay which becomes released when a train is approaching said intersection in either said third or said fourth approach sections, and means for causing said pair of mechanisms to operate said pair of switches to their normal or reverse positions according as said first or second approach relay respectively is released provided the other approach relay is not released.

8. In combination, a first stretch of railway track including an intersection with a second stretch of railway track, said intersection including a pair of track switches each operable to a normal position to condition said intersection for the passage of traffic in said first stretch and to a reverse position to condition said intersection for the passage of traiiic in said second stretch, a pair of mechanisms for operating said switches between their two positions, a first and a second approach section in said first stretch. third and a fourth approach section in said second stretch, a first approach relay which becomes released when a train is approaching said intersection in either said first or said second approach sections, a second approach relay which becomes released when a train is approaching said intersection in either said third or said fourth approach sections, means for causing said pair of mechanisms to operate said pair of switches to their normal or reverse positions according as said first or second approach relay respectively is released provided the other approach relay is not releasecha first pair of signals one for each approach section of said first stretch, a second pair of signals one for each approach section of said second stretch, and means governed by said approach relays for selectively controlling said signals.

9. In combination, a stretch of railway track including a detector section and an approach section each provided with a track circuit including a track relay, a track switch included in said effective when said switch is restored to its initial ing said power mechanism, a normally energized lock 'relay effective when deenergized to disable said control means, a selector lever for conditioning the switch for manual operation including a contact which is closed only when said switch is in its initial condition, a stick circuit for said lock relay including said contact and a front contact of said lock relay, a pick-up circuit for said lock relay including a back contact of the track relay for the detector section, and another pick-up circuit for said lock relay including a front contact of the track relay for the approach section.

11. In combination, a stretch of railway track including a pair of track switches one at each end of said stretch and each operable between normal and reverse positions, a first and second approach section connected with said stretch at one end according as the switch at that end is occupying its normal or reverse position respectively, a third and fourth approach section connected with said stretch. at the other end according as the switch at that end is occupying its normal or reverse position respectively, an approach relay for each approach section, and means controlled by said approach relays for causing the switch at said one end to'assume its normal position when a train approaching said stretch is occupying either said first, third or fourth sections and for causing the switch at the other end of said stretch to assume its normal position when a train approaching said stretch is occupying either said first, second or third approach sections, said means being also efiective to cause the switch at said one end'and the switch at said other end to assume their reverse positions when a train approaching said stretch occupies said second and fourth sections respectively.

12. In combination, a stretch of railway track including a track switch operable between normal and reverse positions. a first approach section and a second approach section connected with said stretch according as said switch is occupying its normal or reverse position respectively, a first approach relay which becomes released when a train is approaching said switch in said first section, a second approach relay which becomes released when a train is approaching said switch in said second section, means effective when one approach relay is released to maintain the other approach relay in its picked up. condition, a first slow releasing relay which becomes deenergized when said first approach relay is released provided said second approach relay is notalready released, a second ,slow releasing relay which becomes deenergized when said second approach relay is released, a mechanism for operating said switchbetween its two positions, and means for causing said mechanism to operate said switch to its normal or reverse position according as said first or said second slow release relay respectively is released provided the other slow release relay is picked up.

13. In combination, -a stretch of railway track including a track switch operable between normal and reverse positions, a first approach section and a second approach section connected with said stretch according as said switch is occupying its normal or reverse position respectively, a first approach relay which becomes re leased when'a train is approaching said switch in said first section, a second approach relay which becomes released when a train is approaching said switch in said second section, means effective when one approach relay is released to maintain the other approach relay in its picked up condition, a first slow release relay which becomes deenergizedwhen said first ap-- proach relay becomes released, a second slow release relay which becomes deenergized when said second approach relay becomes released,

means'effective to prevent the deenergization of I said first slow release relay if said second approach relay is alreadyv released thereby insuring that if the first andise'cond approach sections become occupied simultaneously the second slow release relay will become released, and means for causing said switch to assume its normal or reverse position according as said first or said second slow release relay respectively be. comes released provided the other slow release relay'remains picked up. f

14. In combination, a stretch of railwaytrack including a pair of track switches one at each end of said stretch and each operable between I normal and=reverse positions, a first and second approach section connected with said stretch at one end according'as the switch at that end is occupying its normal, or reverseposition respectively, a third and fourth approach section connected with-said stretch'at the other end according as the switch atthat end is occupying its normal or reverse position respectively, an approach relay for eachapproach section, means eiiective when a train is approachingsaid stretch in said first section to release the approach relay for that section provided the approach relay for the second section is picked up, means effective when a train is approaching said stretch in said second section to release the approach relay for that section provided the approach relays for the first, third, and fourth sections are all picked up, means effective when a train is approaching said stretch in said third section to release the approach relay for that section provided the ape proach relay for the fourth, section is picked up, means effectivewhen a train is approaching said stretch insaid fourthsection to release the approach relay for that section provided the approach relays for thefirst, second and third sections are all picked up, and means governed by said approach relays for controlling said switches in such a. manner that trains entering said stretch from the first or second approach sections will depart via said third approach section iii) and trains entering said stretch from the third or fourth approach sections will depart via said first approach section.

15. In combination, a stretch of railway track,

a first switch at one end of said stretch operable to a reverse position to connect a first approach section thereto, a second switch at the other end of said stretch operable to a reverse position to connect a second approach section thereto, a first approach relay and a second approach relay which become released when the first and second approach sections respectively become occupied by a train approaching said stretch, a first and a second slow release relay which become deener- 'gized when the first and second approach relays respectively become released, means effective to prevent the'deenergization of said second slow release relay if the said first approach relay is released thereby insuring release of said first slow release relay if said first and second approach sections become occupied simultaneously, and means effective to operate said first switch to its reverse position or said second switch to its reverse position according as said first or second slow release relay respectively is released provided the other slow release relay is picked up. 16. In combination, a first stretch of railway track provided with a detector section including an intersection with a second stretch of railway track, said intersection including a pair of track switches operable to a normal position to condition the intersection for trafiic passing in said first stretch or to a reverse position to condition the intersection for trafiic passing in said second stretch, a pair of mechanisms one connected to each switch, control means to cause the mechanisms to automatically position the switches to correspond totraffic conditions in the two stretches, a lock relay effective when deenergized to disable said control means, means for deener- ,gizing said lock relay when either of said switches is conditioned for manual operation, and means for energizing said lock relay when both switches are restored to their initial condition provided said detector section is occupied or provided certain approach zones in both stretches are all unoccupied.

17. In combination, a stretch of railway track including a track switch operable between a normal position and a reverse position, a first approach section connected with said stretch when said switch is occupying its normal position, a second approach section connected with said stretch when said switch is occupying its reverse position, means for causing said switch to assume it normal position or its reverse position according as said first section or said second section respectively becomes occupied by a train, and means including a slow acting relay whereby one section takes precedence over the other when both sections become occupied simultaneously.

18. In combination, a stretch of railway track including a track switch operable between a normal position and a reverse position, a first approach section connected with said stretch when said switch is occupying its normal position, a second approach section connected with said stretch when said switch is occupying its reverse position, means for causing said switch to assume its normal position or its reverse position according as said first section or said second section respectively becomes occupied by a train, and time controlled means for causing one section to take precedence over the other when both sections become occupied simultaneously.

19. In combination, a stretch of railway track including a track switch operable between a normal position and a reverse position, a first approach section connected with said stretch when said switch is occupying its normal position, a second approach section connected with said stretch when said switch is occupying its reverse position, each of said approach sections having associated therewith a relay having a movable contact movable between a normal position and an operating position, each of said relays being conditioned to efiect movement of its movable contact from its normal position to its operating position when the associated track section becomes occupied by a train approaching said switch, each of said relays having means operative on movement of its movable contact to its operating position to maintain the movable contact of the other of said relays in its normal position, a mechanism for operating said switch between its two positions, and means for causing said mechanism to operate said switch to its normal or its reverse position according as the movable contact of one or the other of said relays is in its operating position.

20. In combination, a stretch of railway track including a track switch operable between a normal position and a reverse position, a first approach section connected with said stretch when said switch is occupying its normal position, a second approach section connected with said stretch when said switch is occupying its reverse position, each of said approach sections having associated therewith a relay having a movable contact movable between a normal position and an operating position, each of said relays being conditioned to effect movement of its movable contact from its normal position to its operating position when the associated track section becomes occupied by a train approaching said switch, each of said relays having means operative on movement of its movable contact to its operating position to maintain the movable contact of the other of said relays in its normal position, a mechanism for operating said switch between its two positions, and means for causing said mechanism to operate said switch to its normal or its reverse position according as the movable contact of one or the other of said relays is in its operating position, one of said relays having associated therewith manually controlled means for efiecting movement of the movable contact thereof from its omrating position to its normal position.

21. In combination, a stretch of railway track including a track switch operable between a normal position and a reverse position, a first approach section connected with said stretch when said switch is occupying its normal position, a second approach section connected with said stretch when said switch is occupying its reverse position, each of said approach sections having associated therewith a relay having a movable contact movable between a normal position and an operating position, each of said relays being conditioned to effect movement of its movable contact from its normal position to its operating position when the associated track section becomes occupied by a train approaching said switch, each of said relays having means operative on movement of its movable contact to its operating position to maintain the movable contact of the other of said relays in its normal position, a mechanism for operating said switch between its two positions, and means for causing said mechanism to operate said switch to its normal or its reverse position according as the movable contact of one or the other of said relays is in its operating position, each of said relays having associated therewith means for maintaining its movable contact in its normal position when the associated approach section becomes occupied by a train receding from said intersection.

22. In combination, a first stretch of railway track including an intersection with a second stretch of railway track, said intersection 'including a pair of track switches each operable to a normal position to condition said intersection for the passage of trafiic in the first stretch and to a reverse position to condition said intersection for the passage of trafiic in the second stretch, a pair of mechanisms for operating said switches between their two positions, a first and a second approach section in said first track stretch, a third and a fourth approach section in said second track stretch, each of said track stretches having associated therewitha relay hav ing a movable contact movable between a normal position and an operating position, each of said relays being conditioned to effect movement of its movable contact from its normal position to its operating position when either of the approach sectionsfor the associated track stretch becomes occupied by a train approaching said intersection, each of said relays having means operative on movement of its movable contact to its operating position to maintain the movable contact of the other of said relays in its normal position, and means for causing said mechanisms to operate said switches to their normal or reverse positions according as the movable contact of one or the other of said relays is in its operating position.

23. In combination, a stretch of railway track including a track switch operable between a nor mal and reverse position, a mechanism for operating said switch between its two positions, a first approach section and a second approach section connected with said stretch according as said switch is occupying its normal or reverse position respectively, each of said approach sections having associated therewith an approach relay each controlling a circuit for energizing the winding of the other, each of said relaysalso controlling the one of the circuits by which current is supplied to its own winding, a first slow acting relay, a circuit controlled by one of said approach relays for energizing the winding of said slow acting relay, a circuit controlled by the other of said approach relays and by said slow acting relay for also supplying current to the winding of said slow acting relay, a second slow acting relay, a circuit controlled by said other of said approach relays for supplying current to the winding of said second slow acting relay, and means for causing said mechanism to operate said switch to its normal or reverse position according as the winding of the first or second slow acting relay is energized.

' 24. In an automatic crossing signalling system, the combination with a railway crossing including two railway tracks crossing each other,

a signal for each track for governing the movement of railway vehicles over said crossing, a route relay for each signal, an approach relay for each signal, a circuit for each of said route relays and each of said circuits closed for energizing its route relay only when the approach relay forits signal is deenergized and the approach relay for the other signal is energized so that only one of said route relays may be energized at one time, an approach section for each signal including a track circuit and a track relay, circuit means for each approach relay normally closed for energizing its approach relay but becoming opened when the approach section for its signal becomes occupied, retaining circuit means 'for keeping each of said approach relays energized when the other approach relay becomes deenergized, a clearing circuit for each signal including a front contact of its associated route relay, and means effective if one of said signals is at proceed and both of said approach sections are occupied for deenergizing the route relay for said one signal and putting said one signal to stop and causing the other route relay to be energized to clear its associated signal irrespective of the order in which said approach sections were occupied.

25. In an automatic crossing signalling system, the combination with a railway crossing including two railway tracks crossing each other, a signal for each track for governing the movement of railway vehicles over said crossing, a 2

route relay for each signal, an approach relay for each signal, a circuit for each of said route relays and each of said circuits'including a back contact of the approach relay for its signal and a front contact of the approach relay for the other signal so that only one of said route relays may be energized at one time, an approach section for each signal including a track circuit and a track relay, circuit means for each approach relay normally closed for energizing its approach relay but becoming opened when the approach section for its signal becomes occupied, retaining circuit means for keeping each of said approach relays energized when the other approach relay becomes deenergized, a clearing circuit for each signal including a front contact of its associated route relay, and manually operable means effective if operated when one of said signals is indicating proceed and bothof said approach sections are occupied for deenergizing the route relay for said one signal and putting said one signal to stop and causing its associated signal irrespective of the order in which said approach sections were occupied.

26. In an automatic crossing signalling system, the combination with a railway crossing including two railway tracks crossing each other,

. the other route relay to be energized to clear,

a signal for each track for governing the movement of railway vehicles over said crossing, a route relayior each signal, an approach relay for each signal, a circuit for each of said route relays and each of said circuits closed for energizing its route relay only when the approach relay for its signal is deenergized and the approach relay for the other signal is energized so that only one of said route relays may be energized at one time, an approach section for each signal including a track circuit and a track relay, a pick-up circuit for each of said approach relays controlled by a front contact of the track relay for the approach section for its sigare occupied for deenergizing the route relay for in;

said one signal and'putting said one signal to stop and causing the other route relay to be energized to clear its associated signal after the lapse of a predetermined time irrespective of the order in which said approach sections were occupied.

-27. In an automatic crossing signalling system, the combination with a railway crossing including two railway tracks crossing each other, a signal for each track for governing the movement of railway vehicles over said crossing, a

route relay for each signal, an approach relay for each signal, a circuit for each of said route relays and each of said circuits including a back contact of the approach relay for its signal and a front contact of the approach relay for the other signal so that only one of said route relays may be energized at one time, a pick-up circuit for each of said approach relays controlled by a front contact of the track relay for the approach section for its signal, a stick circuit for each of said approach relays including a front contact of its own and controlled by a back contact of the other approach relay, an approach section for each signal including a track circuit and a track relay, a clearing-circuit for each signal including a front contact of its associated route relay, and manually operable means effective if operated when one of said signals is indicating proceed and both of said approach sections are occupied for deenergizing the route relay for saidone signal and putting said one signal to stop and causing the other route relay to be energized to clear its associated signal after the lapse of a predetermined time interval irrespective of the order in which said approach sections were occupied.

28. In a traffic controlling system for railroads, a track layout having a first stretch of track crossed by a second stretch of track, signals for governing traffic over each track, an approach track section for each signal, a neutral relay for each track, circuit means for energizing each of said relays when the signals for their respective tracks are at stop, circuit means for causing either of said relays to be deenergized when an approach section for that track isoccupied, a stick relay for each of said neutral relays, means for energizing each of said stick relays if a train passes from an approach section for its track into a section in advance of the associated signal, means for retaining each or said stick relays in the energized condition while the opposite approach track section for the same track is occupied, means controlled by each of said stick relays in the energized condition for energizing the associated neutral relay while said opposite approach section for the same track is occupied, circuit means whereby when either one of said neutral relays is deenergized the other neutral relay cannot become deenergized, and circuit means for causing a signal to clear for each track only when said relay for that track is deenergized and said relay for the other track is energized.

29. In a traffic controlling system for railroads, a track layout having a plurality of conflicting routes, signals for governing traffic over each route, an approach track section having a track relay associated therewith for each signal, circuit means for clearing each, signal when a train occupies the approach track section for that signal, a neutral relay'for each track, circuit means for energizing each of said neutral relays and for causing each of said neutral relays to be deenergized when a train occupies an approach track section for that track, two stick relays for each track one for each direction of trafiic movements, means responsive to traffic movements in either direction over each track for eifecting energization of the stick relay for that direction and for preventing energization of the stick relay for the opposite direction, means controlled by each of said stick relays in the energized condition for energizing the neutral relay for its track while the approach track section for its direction of trafiic movements is unoccupied and the approach track section for the opposite direction of traffic movements is occupied, circuit means responsive to the operation of said neutral relays for allowing signals on only one of all conflicting tracks to clear at any one time, and means responsive to the operation of Said track relays for each track for allowing only one of all conflicting signals on that track to clear at any one time.

30. In a trafiic controlling system for railroads; a track layout having a first stretch of track crossed by a second stretch of track; signals for governing trafiic over each stretch of track; an approach track section having a track relay as,- sociated therewith for each signal; circuit means for causing each signal to clear when a train occupies the approach track section for that signal; circuit means responsive tothe operation of said track relays for allowing only one signal on each track to clear at any one time; a neutral relay for each track; circuit means for energizing each of said neutral relays; circuit means for causing each of said neutral relays to be deenergized when a train occupies an approach track section for that track; two stick relays for each track one for each direction of trafiic movements, means responsive to traffic movements in either direction over each track for effecting energization of the stick relay for that direction and for preventing energization of the stick relay for the opposite direction, a time contactor for each track, means controlled by each of said time contactors for conditioning either of the stick relays for its track-for energization in response to a traific movement in the opposite di rection, means controlled by each of-said stick relays in the energized condition for energizing the neutral relay for its track while the approach track section for its direction of traffic movements is unoccupied and the approach track section for the opposite direction of traffic movements is occupied, circuit means responsive to the operation of said neutral relays for allowing signals on only one track to clear at any one time; and circuit means responsive to the operation of said contactor on each track for causing a signal on that track to change its indication from clear to stop-and for allowing-a signal on the other track to be cleared only at the end of a predetermined time interval.

31. In'a trafilc controlling system for railroads, a track layout having a first stretch of track crossed by a second stretch of track, signals for governing trafiic over each track, an approach track section having a track relay associated therewith for each signal, circuit means for-clear,- ing each of said signals when an approaching train occupies its respective approach track section, a neutral relay for each track, circuit means for energizing each of said neutral relays and for deenergizing each of said relays when a train occupies an approach section for that track, two stick relays for each track one for each direction -of trafiic movements, means responsive to trafiic movements in either direction over each track for efiecting energization of the stick relay for that direction and for preventing energization of the stick relay for the opposite direction, means controlled by each of said stick relays in the energized condition for energizing the neutral relay for its track while the approach track section for its direction of traflic movements is unoccupied and the approach track section for the opposite direction of trafilc movements is occupied, circuit means for preventing the energization of signals on more than one track at any one time, means dependent upon the operation of said track relays for allowing only one signal on each track to clear at any one time, and means included in the control circuit of each signal for checking the deenergized condition of the stick relay for the opposite direction'of traffic movements and for checking the position of the signal mechanism of the signals for the conflicting track.

GEORGE R. PFLASTERER.

CERTIFICATE OF CORRECTION.

Patent No, 2,208,685. July 2;, 191m.

- GEORGE R. PFLASTERER. It is hereby certified that error appears in the printed specification of the above numbered patent requiring'correction as follows: Page 5, second column, line 57, claim 1, for the word in" read -to--; page 6, first column, line 71;, claim. 5, for "to said read --as said--; page 10, first column, lines 25, 2A, and 25, claim 27, strike out the words and comma "an approach section for each signal including a track circuit and a track relay," and insert the same after "time," in line 17, same claim; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 10th day of September, A. D. 1910.

Leslie Frazer, (Seal) Acting Commissioner of Patents. 

